1. Field of the Invention
This invention relates generally to improvements in ladders. More specifically, the invention is directed to improvements in marine ladders wherein a support frame for the ladder safely secures a ladder portion thereto, and wherein catch mechanisms for the ladders are constructed to be permanently affixed to the ladders.
2. Description of the Related Art
The recreational and competitive sport of boating requires mastery of many land and sea-based maneuvers to safely operate a boat. One such needed maneuver arises in connection with boarding and debarking the boat from or to a stationary or floating dock. Typically, marine ladders have been used to load and unload the boat""s crew and passengers. Prior marine ladders generally comprise a support frame that is fixedly mounted to the dock, and a ladder portion which slidably engages with the support frame so that the ladder portion can be adjusted to a desired height for use. The underside rungs of the ladder portion are u-shaped and so engage with a catch mechanism on the support frame to secure the ladder portion to the support frame after the desired height has been set.
The construction of the support frame and catch mechanism of prior art marine ladders has caused a great deal of problems in the past. The catch mechanism in prior art marine ladders is formed from a transverse bar that is surface welded at either of its ends to two upright or vertical support rods that are ultimately secured to the dock. FIGS. 7 and 8 illustrate this arrangement. The catch mechanism 10 comprises a catch tyne 20 which is integrally formed, such as by welding or metal bending, with transverse bar 30. On either end of transverse bar 30 is mounted a triangular shaped gusset 40 which extends downward from the underside of bar 30. Gussets 40 are surface welded to the vertical support rods 50 to further secure the catch mechanism 10 to the vertical support rods 50.
The problem which arises from this arrangement is that the gussets 40 are subjected to severe strains from use, weather and the harsh conditions found at and around salty ocean water, lakes and other bodies of water. Since the gussets 40 are separate structures which are merely surface welded to the support rods 50 and transverse bar 30, the joints 60 between the gussets 40, support rods 50, and transverse bar 30, defined by the welds, form weak areas on the marine ladder and quickly degrade and sometimes fracture due to the stresses placed on the catch tyne 20 when users employ the marine ladder to get in to and out of the boat from or to the dock. Furthermore, the deleterious effects of weather and corrosion attack the joints 60. Within a relatively short amount of time, the joints 60 decay and the catch mechanism 10 detaches from the support rods 50 and/or the transverse bar 30. This result is a dangerous situation which makes boating unsafe, and can cause severe injuries to individuals using such prior art marine ladders.
There accordingly exists a long-felt need in the art for marine ladders which safely and effectively allow boaters to climb in to and out of boats from or to docks over long or extended periods of time. Prior art marine ladders do not satisfy this long felt need.
The aforementioned long-felt needs are met, and problems solved, by marine ladders having secure catch and securement mechanisms provided in accordance with the present invention. The inventive marine ladders include a catch mechanism that is adapted to engage the underside of rungs of a relatively movable ladder portion to secure the ladder portion to the support frame when the marine ladder is being used. The catch mechanism preferably comprises a transverse bar having at least one catching tyne. The transverse bar is secured at its two ends to vertical support rods of a support frame for the ladder. At least one catch tyne is fixedly secured to the transverse bar and is not subject to loosening or detachment therefrom. Preferably, the tyne is directly affixed to the transverse bar without the use of gussets or any other external members or elements that may require a separate means of securment, as for example by welding.
The catch tyne is secured to the transverse bar by any number of securing devices, such for example as screws, rivets, and pins. Additionally, the catch tyne may be further secured to the transverse bar by a watertight and impermeable adhesive that is not subject to degradation due to weather or the difficult environment typically imposed on marine ladders from salt water, lakes and river bodies containing minerals and other contaminants. Even more preferably, the support frames comprise guide members that engage the support rods of the ladder portions to allow for smooth and safe adjustment of the height of the ladder portions. Still more preferably a set of stop members is disposed on the vertical support members of the ladder portion for setting the maximum height allowed by the ladder portion and for relieving undo stresses on the catch tyne.
Marine ladders of the present invention ensure safe loading and unloading of boat passengers and crews to and from dock areas. The inventive marine ladders are of simple construction and are economical to manufacture. Such results have not heretofore been achieved in the marine ladder art.
These and other features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.